Transponder for tires

ABSTRACT

The invention relates to a transponder which is mounted in a tire. The transponder includes at least a transponder chip and a transponder antenna and is embedded in a substrate. The substrate is connected to an inner side of the tire by a connecting structure. In order to provide a transponder with the longest possible service life, the substrate is decoupled from the inner side of the tire via a connecting structure in the form of a soft or gliding support in such a manner that no or only minimum mechanical stresses are transmitted to the substrate. The connecting structure is arranged between the substrate and the inner side of the tire.

FIELD OF THE INVENTION

[0001] The invention relates to a transponder which is mounted on atire. The transponder includes at least a transponder chip and atransponder antenna and is embedded in a substrate. The substrate isconnected to the inner side of the tire via a suitable means.

BACKGROUND OF THE INVENTION

[0002] Transponders are utilized in tires for various tasks. One ofthese tasks is especially tire identification which enables anautomobile manufacturer to rapidly and automatically determine fromwhich tire factory a specific tire was delivered. Other tasks caninclude: a monitoring of pressure, a temperature measurement, themeasurement of mechanical stress conditions in the tire or a measurementof running capacity of the tire which has already been travelled. Moderntransponders comprise an electronic component or chip in which sensorelements can be arranged as well as an antenna connected to thiselectronic component.

[0003] A problem with tire transponders is associated with thearrangement of the transponder in the tire. German patent publication4,426,022 discloses, for example, a transponder which is arranged in aso-called container which, in turn, is fixed to the tire inner side withadhesive. The container functions as a housing and the container as wellas a stiffer carrier layer, which lies between the transponder and theinner side of the tire, are fixedly connected to the transponder. Asignificant disadvantage of this composite arrangement is that highloads are transmitted to the transponder because of the occurringdeformations during the operating state of the tire. These loads eitherlead to damage of the transponder antenna or to a breakage of theconnecting location between transponder chip and transponder antenna.The transponder can then no longer be used for data transmission becauseof the irreversible damage.

SUMMARY OF THE INVENTION

[0004] It is an object of the invention to provide a transponder forbuilding into a tire which transponder has a service life as long aspossible.

[0005] The transponder arrangement of the invention is for mounting in atire defining an inner side. The transponder arrangement includes: asubstrate; a transponder embedded in the substrate and including atransponder chip and an antenna; a connecting structure disposed betweenthe substrate and the inner side of the tire; the connecting structurebeing in the form of a soft or sliding support; and, the substrate beingdecoupled from the inner side by the connecting structure in such amanner that no or only minimal stresses are transmitted to thesubstrate.

[0006] An advantage of the invention is especially that the loads, whichact upon the transponder, are significantly reduced because of the softor gliding support. In the arrangement of the invention, the portion ofthe thrust stresses and normal stresses, which are transmitted to thetransponder, are negligibly low. This effect applies likewise for thealternate bending stress load which acts on the transponder in theoperating state of the tire and is greatly reduced because of theachieved decoupling. The transponder thereby has, in total, asignificantly longer service life.

[0007] In an advantageous embodiment of the invention, the connectingstructure is configured as a cushion support. In this form ofdecoupling, a soft material cushion is mounted between the transponderand the inner side of the tire. The cushion support is a construction,which can be especially simply realized in order to achieve adecoupling.

[0008] In another advantageous embodiment of the invention, the cushionsupport is made of a silicone layer. Silicone has a viscous elasticmaterial characteristic and is therefore especially suitable as a softsupport. Furthermore, this material can be easily processed.

[0009] In a further advantageous embodiment of the invention, thecushion support comprises an air cushion, gel cushion or foam cushion.With these materials, a soft support is likewise obtained in a simplemanner.

[0010] In a further advantageous embodiment of the invention, thecushion support is made of cellular rubber. Here, the cushion support isa closed-cell elastomer foam which has additional dampingcharacteristics in order to compensate for the occurring loading.

[0011] In a further advantageous embodiment of the invention, thecushion support is a leg-like or strut-like structure. The leg-likeconnecting structure contributes to an increased decoupling betweentransponder and the inner side of the tire.

[0012] According to still another feature of the invention, thesubstrate and the cushion support are covered by a patch which isconnected to the inner side of the tire. In this way, an adhesiveconnection between the transponder, which is embedded in the substrate,and the cushion support is unnecessary. As a consequence, onlynegligible thrust stresses are transmitted between the transponder andthe cushion support.

[0013] According to another feature of the invention, the substrate iscovered by a patch which is connected to the inner side of the tire. Apartition medium is disposed between the substrate and the inner side ofthe tire and the substrate can slideably move on this partition medium.In this arrangement, the transponder, which is embedded in thesubstrate, slideably moves on the partition medium whereby only very lowthrust stresses are transmitted to the transponder. An advantageousembodiment of the partition medium is a foil.

[0014] In another advantageous embodiment of the invention, a partitionmedium is arranged between the substrate and the patch. The partitionmedium is, for example, in the form of a powder, gel or a solution andeliminates an adhesion between the transponder, which is embedded in thesubstrate, and the rubber material of the patch. In this way, only lowthrust stresses can be transmitted from the patch or covering.

[0015] In a further advantageous embodiment of the invention, the patchis permeable to air at least at one location. In this way, the same airpressure is present in the hollow space between the patch and the innerside of the tire whereby the load on the transponder during operation ofthe tire is less.

[0016] In a further advantageous embodiment of the invention, thesubstrate is supported in a fluid in a cavity. The transponder isembedded in the substrate and supported to float freely in the fluid sothat neither thrust nor normal stresses can be transmitted to thesubstrate.

[0017] In a further advantageous embodiment of the invention, it isprovided that the substrate is connected to the inner side of the tirevia at least one connecting leg which defines the connecting structure.In this embodiment, a mushroom-shaped connecting structure is presentwhich is characterized likewise by a high degree of decoupling betweenthe transponder and the inner side of the tire.

[0018] In another embodiment of the invention, the substrate isconnected to the connecting leg via a latch or snap connection. In thisway, the transponder can be easily connected to the connecting leg and,if necessary, can again be separated therefrom.

[0019] In another advantageous embodiment of the invention, thesubstrate has an arcuately-shaped housing contour adapted to the innerside of the tire. In this way, it is ensured that the transponder doesnot come into contact with the inner side of the tire even duringcontact and during non-contact.

[0020] In still another embodiment of the invention, the substrate ismounted in a patch or covering which is fixedly connected to the innerside of the tire only at one or several component regions. In thisembodiment, only minimum thrust stresses are transmitted to thetransponder.

[0021] In still another embodiment of the invention, a partition mediumis disposed between the patch and the inner side of the tire. Thepartition medium prevents an adhesion between the patch and the innerside of the tire whereby the decoupling effect is increased.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The invention will now be described with reference to thedrawings wherein:

[0023]FIG. 1 is a schematic of a transponder embedded in a substrate andarranged on the inner side of a tire with the transponder having aconnecting structure in the form of a cushion support;

[0024]FIG. 2 is a schematic of a cushion support having strut-shapedconnecting structures;

[0025]FIG. 3 is a connecting structure covered by a patch;

[0026]FIG. 4 is a connecting structure wherein a partition medium isdisposed between the transponder and the inner side of the tire;

[0027]FIG. 5 is a schematic of a transponder which is mounted in a fluidin a cavity of the patch;

[0028]FIG. 6 is a transponder, which is embedded in a substrate andwhich is connected to the inner side of a tire via two connecting legs;

[0029]FIG. 7 is a schematic of a transponder, which is embedded in asubstrate, and which is connected to the inner side of a tire via atube-shaped holder;

[0030]FIG. 8 is a schematic of a transponder, which is embedded in asubstrate, and which is connected to a connecting leg via a snapconnection;

[0031]FIG. 9 is a schematic of a transponder, which is mounted in apatch, and which is connected to the inner side of a tire only at onecomponent region; and,

[0032]FIG. 10 is a plan view of the embodiment shown in FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0033]FIG. 1 shows a transponder 1, which is embedded in a substrate 4,and is mounted on the inner side 3 of a tire with a connecting structurein the form of a cushion support 2. The transponder comprises atransponder chip 5 and an antenna coil 19 which are embedded in asubstrate 4. The substrate 4 functions as a housing and can, forexample, be composed of epoxy resin, a plastic, rubber, elastomer or afoil. The transponder 1 is therefore not in direct connection with thecushion support 2 which defines the connecting structure to the innerside 3 of the tire. The cushion support 2 can be made of various softmaterials and especially of a silicone material. It is likewise possiblethat the cushion support comprises an air gel or a foam cushion. Thesubstrate 4 is, for example, connected to the cushion support 2 via anadhesive connection. In the substrate 4, an opening 6 can be providedvia which the air pressure can be measured which is present in thehollow space of the tire. This opening 6 is likewise provided in theembodiments in the following FIGS. The cushion support 2 has thefunction to decouple the transponder 1 and the substrate 4 surroundingthe same from the inner side of the tire in that the cushion support 2absorbs most of the deformations and stresses coming from the inner sideof the tire. While the occurring deformations and mechanical stressesare very large on the side of the cushion support 2 facing toward theinner side 3 of the tire, only negligible stress conditions ordeformations are present on the opposite-lying side of the cushionsupport 2. In this way, hardly any stresses or deformations aretransmitted to the enclosing substrate 4 of the transponder 1 wherebythe service life of the transponder 1 is considerably lengthened.

[0034]FIG. 2 shows a cushion support 2 having a leg-shaped or strut-likeconnecting structure. In FIG. 2 as well as in the following FIGS. , thetransponder with the transponder chip and transponder antenna are notexplicitly shown. Only the substrate 4 is shown in each case in whichthe transponder with its components is embedded. The same applies to theopening 6 in FIG. 1. The cushion support 2 distinguishes from the firstembodiment of FIG. 1 in that the cushion support has several recesses 9.These recesses 9 contribute to reducing the stiffness of the cushionsupport. In this way, the stress transfer from the inner side of thetire to the transponder 1 or to the surrounding substrate is furtherreduced.

[0035]FIG. 3 shows a connecting structure covered by a patch 10. Thisembodiment corresponds essentially to the first embodiment of FIG. 1.The transponder, which is embedded in the substrate 4, is held on theinner side 3 of the tire with the aid of a patch 7 whereby no adhesiveconnection is needed between the cushion support 2 and the substrate 4surrounding the transponder. Only minimal thrust stresses can betransmitted because of the free movability of the substrate 4 on thecushion support 2.

[0036]FIG. 4 shows a connecting structure wherein a partition medium 11is arranged between the substrate 4 and the inner side 3 of the tire.The partition medium 11 can, for example, be made of a plastic foil onwhich the transponder 1, which is embedded in the substrate 4, can slidefreely. In this way, only negligible thrust stresses are transmitted. Apartition means should likewise be provided between the patch 10 and thesubstrate 4 so that an adhesion to the rubber material of the patch isavoided. A fat layer, oil layer, powder layer or silicone layer canserve as a partition means and is applied as a solution or paste to thesubstrate 4. It is likewise conceivable that the total substrate 4 iscoated with such a partition means in order to be able to do without thepartition medium 11. The partition means, as the partition medium 11,has the function to prevent an adhesion between the substrate 4 and thesurrounding rubber material. In this way, only slight thrust stressescan be transmitted to the substrate 4 which would otherwise lead todamage of the transponder.

[0037]FIG. 5 shows a transponder, which is embedded in a substrate 4,and which is arranged in a fluid 12 in a cavity of the patch 10. Thetransponder is embedded in the substrate 4 and is supported so as tofreely float in the fluid so that neither thrust stress nor normalstress can be transmitted to the substrate 4. A silicone oil can beused, for example, as the fluid.

[0038]FIG. 6 shows a transponder embedded in a substrate 4. Thetransponder is connected to the inner side 3 of the tire via twoconnecting legs. The connecting legs comprise a flexible material and,because of the low stiffness of the connecting structure, only a minimumstress is transmitted to the substrate 4.

[0039]FIG. 7 shows a transponder embedded in a substrate 4 which isconnected to the inner side 3 of the tire via a tubularly-shaped holder14. The substrate 4 therefore is connected to the tubularly-shapedholder 14 only at its outer edges. The holder 14 is, in turn, connectedto the inner side 3 of the tire, for example, via an adhesiveconnection.

[0040]FIG. 8 shows a transponder, which is embedded in a substrate 4,and which is connected to a connecting leg 20 via a snap connection 15.In this embodiment, the substrate 4 has a cutout which, together withthe mushroom-shaped end 13 of the connecting leg 20, ensures aform-tight connection. Furthermore, the substrate 4 has a sickle-shapedouter contour which is adapted to the contour of the inner side of thetire. In this way, it is ensured that the substrate 4 is not in contactwith the inner side 3 of the tire.

[0041]FIG. 9 shows a transponder arranged in a patch 16. The patch 16 isconnected to the inner side 3 of the tire in only a component region.The substrate 4 is completely embedded in the patch 16. Furthermore, apartition medium can be provided between the patch 16 and the inner sideof the tire which prevents an adherence of the patch 16 to the innerside 3 of the tire. In this way, no thrust stresses can, in turn, betransmitted to the transponder. The component connecting region 18 ofthe patch 16 can, for example, be connected to the inner side 3 of thetire by an adhesive.

[0042]FIG. 10 is a plan view of the embodiment of FIG. 9. The circle 4shown in phantom outline shows the outer contour of the transponderembedded in the substrate 4. The patch 16 is connected to the inner sideof the tire only via the partial connecting structure 18.

[0043] This application claims priority from German patent application102 43 441.7, filed Sep. 18, 2002, and said German patent application isincorporated herein by reference.

[0044] It is understood that the foregoing description is that of thepreferred embodiments of the invention and that various changes andmodifications may be made thereto without departing from the spirit andscope of the invention as defined in the appended claims.

What is claimed is:
 1. A transponder arrangement for mounting in a tiredefining an inner side, the transponder arrangement comprising: asubstrate; a transponder embedded in said substrate and including atransponder chip and an antenna; a connecting structure disposed betweensaid substrate and said inner side of said tire; said connectingstructure being in the form of a soft or sliding support; and, saidsubstrate being decoupled from said inner side by said connectingstructure in such a manner that no or only minimal stresses aretransmitted to said substrate.
 2. The transponder arrangement of claim1, wherein said connecting structure is configured as a cushion support.3. The transponder arrangement of claim 1, wherein said cushion supportis a silicone layer.
 4. The transponder arrangement of claim 2, whereinsaid cushion support is an air cushion, gel cushion or foam materialcushion.
 5. The transponder arrangement of claim 2, wherein said cushionsupport is made of cellular rubber.
 6. The transponder arrangement ofclaim 2, wherein said cushion support has a leg-like or strut-likestructure.
 7. The transponder arrangement of claim 2, further comprisinga patch covering said substrate and said cushion support; and, saidpatch being connected to said inner side of said tire.
 8. Thetransponder arrangement of claim 7, further comprising a partitionmedium arranged between said substrate and said inner side of said tire;and, said substrate being disposed on said partition medium so as to beslideably movable thereon.
 9. The transponder arrangement of claim 7,further comprising partition means disposed between said substrate andsaid patch.
 10. The transponder arrangement of claim 7, wherein saidpatch is permeable to air at at least one location.
 11. The transponderarrangement of claim 7, wherein said patch has a cavity containing afluid and said substrate is supported in said fluid.
 12. The transponderarrangement of claim 1, wherein said connecting structure is defined byat least one connecting leg for connecting said substrate to said innerside of said tire.
 13. The transponder arrangement of claim 1, furthercomprising a latch or snap connection for connecting said substrate tosaid connecting structure.
 14. The transponder arrangement of claim 1,wherein said substrate has an arcuately-shaped housing contour adaptedto said inner side of said tire.
 15. The transponder arrangement ofclaim 1, further comprising a patch; said substrate being arranged insaid patch; and, said patch being fixedly connected to said inner sideof said tire only at one or several component regions.
 16. Thetransponder arrangement of claim 1, further comprising a patch; and, apartition medium arranged between said patch and said inner side of saidtire.
 17. A tire comprising: a tire wall having an inner side; atransponder arrangement disposed is said tire; said transponderarrangement including: a substrate; a transponder embedded in saidsubstrate and including a transponder chip and an antenna; a connectingstructure disposed between said substrate and said inner side of saidtire; said connecting structure being in the form of a soft or slidingsupport; and, said substrate being decoupled from said inner side bysaid connecting structure in such a manner that no or only minimalstresses are transmitted to said substrate.